1. Field of the Invention
The present invention relates to a magnetic disk cartridge comprising a cartridge frame and, freely rotatably disposed therein, a magnetic disk.
2. Description of the Prior Art
The magnetic disk of a magnetic disk cartridge comprises a medium and a hub. The medium is made from a flexible resin film which has a magnetic recording material bonded to the surface thereof via a binder or the like. The hub is provided at the center of a doughnut-shaped medium, and has an aperture through which the hub engages with a spindle or the like of a device. The hub is generally made from metal, hard plastic or the like.
In the assembly of a magnetic disk, the bonding of the hub to the medium has been performed using an acrylic double coated adhesive film known in the art as the A ring or using a rubber hot-melt adhesive from the viewpoint of the ease of operations.
The conventional magnetic disk cartridges, however, have a danger such that the adhesive strength between the hub and the medium is lowered causing slippage to occur therebetween when the magnetic disk is left or used in a high-temperature environment.
Although the use of a two-pack reaction type adhesive (acrylic) which exhibits an excellent adhesive strength even in a high-temperature environment, has been examined, the use of such an adhesive has a danger such that the initial bonding strength (at the time of bonding the hub to the medium) of the adhesive is so poor that slippage occurs between the hub and the medium at the time of assembly.